Dyson sphere
A Dyson Sphere is a colossal spherical structure constructed around a star, completely surrounding it. The interior of the sphere would absorb the entire energy output of that star, allowing for lifeforms to live on the interior surface almost indefinitely. Such a structure was theorized by 20th century physicist Freeman Dyson in the late 1950s. For the interior of a Dyson Sphere to be habitable to most humanoid lifeforms, the radius of the sphere must be such that habitable temperatures (5 – 30 °C) are maintained. The radius would therefore depend on the size and the energy output of the star around which the sphere would be constructed; if a Dyson Sphere were to be constructed around the Terran sun, the radius would have to be approximately one astronomical unit. At such a radius, the interior surface area would be about 7 × 1016 km2, or 550 million times the entire surface area of the planet Earth. Such a surface area could easily support the lives of many quadrillions of beings. Unsurprisingly, due to the almost immeasurable amounts of effort, resources and time required to construct such an immense structure, only one Dyson Sphere has ever been discovered. This particular sphere encased a G-type star and had a diameter of 200 million kilometers, giving it an internal surface area of approximately 250 million M-class planets. As no radiant sunlight or solar wind escaped from the sphere, starships were not able to detect it until they were almost on top of it. As a result, the [[USS Jenolan|USS Jenolan]] crashed onto it in 2294 after being pulled in by the sphere's immense gravity well while en route to the Norpin colony. In 2369, the [[USS Enterprise (NCC-1701-D)|USS Enterprise-D]] discovered the Jenolan and investigated the sphere. The sphere was deserted because the star around which it was constructed was highly unstable. ( ) Appendices Background A sphere of 1.33 AUs in diameter would be immense. The shots of the Enterprise in close orbit with a visible horizon just behind it, as though it is orbiting any other planet, are impossible (although parallax may account for this). The surface would appear to be perfectly flat for millions of miles. Another issue of scale occurs when the Enterprise triggers the automated entry system. It is flung toward the central star at nearly light speed (given that the estimated time to impact the star was reported to be approximately equal to the time light takes to travel 1 AU). Surely no species capable of building a Dyson Sphere would design such a flawed entry process, unless perhaps it was intended to be a method of disposing of unauthorized entrants. It is worth noting that the materials needed to enclose every single point in space that far away from a star would require the entire mass of many, many, many planets - probably all of the non-stellar matter in the system would have to be converted into sphere components. Additionally, a Dyson Sphere would retain all energy produced by the star, and would somehow have to radiate much of this into space to maintain a habitable surface temperature. One possible way of conserving such vast quantities of energy without emitting any visible radiation (as seen on-screen) would be to convert all the energy to mass - essentially using a replicator-like technology to create the many, many, many planets' worth of matter necessary to construct the whole sphere. Another possible way of disposing of such vast quantities of energy without emitting any visible radiation (as seen on-screen) would be to create a colossal gravitational field. If this was the case, it would explain why the Enterprise was jolted suddenly upon leaving warp, and possibly why the Jenolan's distress call went undetected until the Enterprise passed within a very short distance. Aprocrypha In book #5 of the Double Helix series (Double or Nothing) Captains Calhoun and Picard encounter a Dyson Sphere constructed by an anti-Federation alliance. Calhoun and Picard eventually succeed in thwarting the alliance and destroying the sphere. In the Deep Space Nine Millennium book series, Chief O'Brien is briefly put into an illusion where he is forced to wander the interior of a Dyson Sphere for several millenia. External links * * Category:Astronomical objects de:Dyson-Sphäre nl:Dyson Bol